Generally, a duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow. The combination of pressure and fan flow measurements are used to determine the ductwork airtightness. The airtightness of ductwork is useful knowledge when trying to increase energy conservation within a building such as a residential home.
Generally, a basic duct leakage testing system includes three components—a calibrated fan, a register sealing system and a device to measure fan flow and building pressure. Supply registers or return air grills are sealed using adhesive tapes, cardboard, or non-adhesive reusable seals. One register or return is left unsealed. The calibrated fan is then connected to that unsealed register. Pressure is monitored in one of the branches of the ductwork while the calibrated fan delivers air into the system. As air is delivered into the ductwork, pressure builds and forces air out of any holes in the various ductwork connections or through the seams and joints of the furnace or air-handler. The tighter the ductwork system (e.g. fewer holes), the less air required from the fan to create a change in the ductwork pressure.
However, this method of duct leakage testing requires administration by a certified person; therefore, this method is time consuming, complicated, and increases the overall cost of installation. There is, therefore, a need for a method to measure duct leakage that is less complicated and reduces overall installation cost.